JP2815595B2 - Prevention of elution of alkali etc. by treating metal oxide on the inner surface of medical glassware - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for preventing elution of alkali and the like from medical glassware fabrics, and more particularly to a method for forming and treating a silica film by an improved CVD method. .

[Conventional technology and problems]

As a method for forming a metal oxide thin film on the surface of the substrate, a liquid phase treatment method represented by a spray method, a spinner method, or the like,
A vapor phase method represented by CVD and PVD is widely practiced.
Each method is selected and implemented depending on the type of oxide, the substrate to be treated, and the expected properties of the oxide film.

Apart from these various liquid-phase processing methods and gas-phase processing methods which are typical thin-film forming methods, since last year, for example, JP-A-48-37786
Japanese Patent Application Publication No. 55-15545 and Japanese Patent Publication No. 55-15545, a thin film forming method using an ultrasonic atomizing method has been actively used.

In this method, a compound is formed in the form of a solution, and ultrasonic waves are applied to the solution to form fine droplets of fine particles, which are transported together with carrier gas, brought into contact with the substrate surface, and decomposed on the surface. Is performed to form a thin film.

This ultrasonic atomization method is preferable from the viewpoints of health and working environment because work can be performed without using a solvent more than necessary. Further, it is considered to be an excellent method in that the work can be performed even under a limited working condition such as a high vacuum or a special inert gas atmosphere as in a generally performed CVD method.

Usually 800Khz for the purpose of atomization in the ultrasonic method
Frequencies in the region of ~ 3 Mc have been used. The particle size distribution of the mist generated varies depending on the frequency used. For example, in the case of a frequency of 3 Mc, mist having a volume ratio of 2 to 3 microns of 50% and a volume of 1.5 to 2 microns of 27% is 27%. Drops can be obtained.

It is known that the size of the atomized particles formed has a significant effect on the state of the film formed together with the reactivity of the compound.

In the case of forming a metal oxide film by an ultrasonic method, for example, in Japanese Patent Publication No. 48-37786, a metal compound is dissolved in a solvent such as alcohol to form a solution having a viscosity of 30 cp or less and atomized by an ultrasonic method to form a substrate. Processed, and
Has proposed a method in which a metal compound is converted into a solution of water or a volatile solvent and subjected to ultrasonic treatment to form an aerosol, and the surface of the substrate is treated with the aerosol.

The metal oxide film formed by the ultrasonic atomization method depends on various factors such as the size and temperature of the atomized particles, the presence or absence of the accompanying solvent, etc., in addition to the type and properties of the metal compound material used, and the state of the film. Nature is largely controlled.

When a silica film is to be formed on the inner surface of glass products or medical glass products (hereinafter referred to as “glass products”) whose opening is smaller than the internal volume of bottles, ampules, syringes, etc. When a flammable compound such as silane gas, alkylsilane, or silane alkoxide used in the above process is used, combustion occurs during the treatment, and the metal oxide is powdered, so that it is difficult to form a transparent and uniform film. Further, when water is used as a solvent, the quality of the compound is often deteriorated, and the surface temperature of the object to be treated is lowered, which is liable to cause deterioration of the film properties, which is not preferable. Furthermore, if alcohols or low boiling solvents that are generally proposed in the past are used, they burn during processing or generate harmful decomposition gases. It is desirable to use silyltetraisocyanate, which is a hydrolyzable compound that causes thermal decomposition at the following temperature and has no flammable hydrocarbon group.

One of the inventors of the present application has previously proposed that a hydrolyzable metal compound containing silyltetraisocyanate is treated by an ultrasonic method to form a metal oxide thin film on the surface of a substrate. (Japanese Patent Application No. 63-172255) A conventional ultrasonic treatment method using a solution or the ultrasonic method according to the earlier application of the present inventors using a specific hydrolyzable compound such as silyltetraisocyanate. When the inner surface of this glass product is treated with silica using an atomized substance (aerosol) atomized by the above, a transparent and dense film that can prevent the elution of alkali compounds such as sodium, calcium, iron, etc. from the glass material is obtained. Could not.

In order to form a transparent silica film on the inner surface of this glass product that can prevent metal compounds from being eluted, it was found that it was necessary to select a CVD treatment with silyltetraisocyanate without using a solvent.

It is known that when a silica film is formed by the CVD method, the glass is treated with silanes such as SiH _4, but this compound is susceptible to combustion decomposition in the atmosphere. For this reason, a special atmosphere is required and implementation is difficult. Further, corrosive decomposition products are generated with silicon halides, which is inconvenient.

When forming a thin film by treating a liquid or solid compound at room temperature by the CVD method, it is necessary to maintain the compound at a temperature at or near the boiling point in order to maintain the specified vapor pressure of the compound during preparation and during the work There is.

However, if a highly reactive compound such as a hydrolyzable or thermally decomposable compound is kept at a high temperature and kept, the decomposition reaction such as a condensation reaction generally proceeds and deteriorates, making it difficult to maintain the work. However, there is a conventional CVD method.

As described above, it has been demanded to solve these problems in the silica film when the metal oxide thin film is formed by the conventional ultrasonic method or CVD method.

When a silica film is to be formed, an ultrasonic method or a CVD method is a method that can be easily applied among conventional methods. But,
When a particularly dense film is to be formed, the object cannot be achieved by the conventional ultrasonic method. Further, in the CVD method, deterioration of the compound due to heating is apt to occur, and the quality of the formed film is liable to be affected. In addition, there is a problem in continuity of work and safety.

Then, one of the present inventors filed the application earlier (Japanese Patent Application No. 63-63).
172255) A method applicable to the treatment of the present glass product using an ultrasonic method was studied.

As a result, both the characteristics of being able to atomize the ultrasonic compound without heating and the quality characteristics of the film formed by the CVD method are synergistically exhibited, and at the same time, the disadvantages of each method are eliminated. A new method for forming a film having a function applicable to the present glass product by a new CVD method has been developed, and the present invention has been achieved.

That is, in the conventional ultrasonic thin film formation, the generated mist droplets are transported by a carrier gas and used for substrate processing. In this method, atomized particles of silyltetraisocyanate generated by an ultrasonic method are not used for treatment but are used as a raw material supply body in a CVD method. In the CVD process, the atomized particles are heated and gasified by the ultrasonic method to form a base mixture with the carrier gas. When the substrate is treated with this substrate mixture, the compound is supplied in the form of a single molecule, so that the film formed on the surface of the substrate is a silica film which is homogeneous at the molecular level unlike the conventional method, and can be applied to the object of the present invention. It was found that

[Summary of the Invention]

Thus, in the present invention, the silyltetraisocyanate atomized droplets generated by the ultrasonic method are transferred by the carrier gas, and heated to a temperature necessary for the silyltetraisocyanate atomized droplets to be gasified in the next step to be gasified. . Further, the present invention proposes an improved processing method of forming a silica film by bringing the compound gas and the carrier gas mixed gas into contact with the inner surface of a medical glass product to be processed.

[Specific description of the invention]

Reference is made to the drawings, which illustrate an example of an apparatus suitable for performing the method of the present invention.

This apparatus uses an ultrasonic oscillator to atomize silyltetraisocyanate and transfers it by carrier gas (A), and a heating part (B) that gasifies a mixture of the transferred carrier gas and silyltetraisocyanate. And a treatment part (C) for treating the medical glass by transferring a mixed gas. Particularly, the treatment part (C) includes a part for intermittent discharge when a continuous treatment is desired in a production line, and a part for a predetermined part. A part to be applied and a part to move the sample are included. Of course, processing can be done in a discontinuous manner.

The generation part (A) is composed of a fixed volume liquid tank 1
An ultrasonic oscillator 2 for oscillating ultrasonic waves of a desired frequency is provided at the bottom of the tank 1, an inlet 3 for a carrier gas such as a nitrogen gas is provided on a side surface, and an opening 5 is provided on a top surface 4 to communicate with a heating portion. I have. Further, a temperature sensor 7 that extends downward and detects the temperature of the liquid 6 contained in the tank 1 is provided on the top surface, and a float switch 8 is provided on the bottom.

The heating portion B includes a cylinder 9 having a fixed height provided above the opening 5 of the liquid tank 1, a heater 10 and a heat insulator 11 around the cylinder 9.
Consists of The cylinder 9 has a lid 12 in which a thermometer 13 is provided, and an opening 14 is provided in the upper side of the cylinder 9 and a processing transfer pipe 15 leading to the next processing part C is attached. I have.

In the processing portion C, the processing transfer pipe 15 is connected to a connection fitting 18 via an air cylinder 17 fixed to an air cylinder unit 16. The unit 16 is slidably mounted on a table 19 in a horizontal direction, and the air cylinder 17 is slidably mounted in a vertical direction. Further, the connection fitting 18 has a discharge needle that can enter the ampoule 20 to be processed.
21 is installed.

The ampoule 20 to be processed is sent to a predetermined position by a grooved roller 23 together with a ruler 22 so as to receive the entry of the discharge needle 21.

The liquid silyltetraisocyanate 6 filled in the liquid tank 1 of the generated portion A now becomes an innumerable mist by the ultrasonic waves oscillated from the ultrasonic oscillator 2. Next, the mist droplets dispersed in the carrier gas introduced from the inlet 3 are
From the heater 10 to the heating portion B, where it is heated by the heater 10 and gasified. The gasified silyltetraisocyanate compound becomes a mixed gas with the accompanying carrier gas and is sent to the processing transfer pipe 15 of the processing part C.

On the other hand, the air cylinder unit 16 is slid to the left in the drawing so that the discharge needle 21 enters the ampoule 20 sent to the predetermined position, and the mixed gas is discharged from the processing transfer pipe 15 through the discharge needle.
It is sent into the ampoule 20 via 21. After a certain amount of feed, the air cylinder 17 slides downward and presses the processing transfer pipe 15 to cut off the feed of the mixed gas.

The silyltetraisocyanate in the mixed gas is sent to the inside of the ampoule 20 and decomposed by contacting the surface thereof, forming a silica thin film thereon, and thus preventing elution of alkali and the like from the glass cloth of the ampoule 20. You can.

If the present invention is described in more detail, a heated carrier gas can be used in the generating portion (A), but for the purpose of the present invention, it is better that the carrier gas has a good room temperature and is not heated. This is to avoid the temperature rise of the compound and the oscillator. When the temperature of the compound or the oscillator rises, the atomization function changes, which is not preferable. Therefore, the generated portion (A) is often worked while usually being air-cooled. Ultrasound equipment usually uses a frequency of about 800 KHz to 3 Mc for this purpose.
If a frequency of less than Mc is used, the atomized particles tend to be coarse and difficult to gasify.

Kyaryagasu uses dehumidified air or N ₂ gas or other inert gas.

The heating portion (B) needs to use a material that can withstand heating. Usually, a material selected from stainless steel, glass and the like is used. And the part generated by heat transfer from this part (A)
It is necessary to keep the temperature from rising.

The heat source is not particularly limited, such as water, steam, oil, and electric heat. The heating temperature is selected according to the compound to be used and the desired operation speed, and is not particularly limited. Generally, it is desirable that the gas mixture with the compound does not agglomerate in the next processing portion (C). For this purpose, the heating temperature of the heating portion (B) is often set to a temperature at which the pressure of the compound at normal pressure is 100 mmHg or more.

It is desirable that the processing portion (C) is kept warm or heated when this route is long or when the temperature of the mixed gas is apt to decrease.

In the case of a silica film, the temperature of the medical glass product to be treated such as an ampoule is preferably as high as possible because sintering proceeds at a higher temperature. Therefore, after the treatment, it is desirable to perform heating at 500 to 650 ° C. for 2 to 3 minutes including the annealing step.

Instead of heating, treatments such as UV treatment, laser treatment, and electron beam treatment are also possible.

〔Example〕

Create the device shown in the drawing, and put silyl tetraisocyanate in the tank of the generating part containing the oscillator that oscillates ultrasonic waves.
200 cc is charged, and nitrogen gas is blown from the inlet at a flow rate of 0.2 l / min. Ultrasonic waves having a frequency of 1.6 to 1.8 Mc are oscillated, and the mist generated by this is transported by a carrier gas and sent to a heating portion through an opening, where it is heated and gasified. The temperature of the heated part was set at 250 ° C., and gasification was measured.

The carrier gas entrainer of this gasified silyl tetraisocyanate is intermittently controlled in synchronization with the moving speed of the medical ampoule and controlled by an air cylinder and a tunable movable tube that discharges into the ampoule. Blowing treatment was performed for seconds. This discharge amount is calculated as 0.0
It was 02 g. The treated product was treated in an annealing furnace at 630 ° C. for 2 minutes to obtain a transparent treated product.

(Confirmation) The treated ampule was charged with pure water, sealed with aluminum foil, and treated in an autoclave at 121 ° C. for 1 hour.

Then a treated water below was the Na analytical results, the density of the SiO ₂ film is significantly Na elution preventing effect than the untreated product treated similarly formed a good homogeneity,
It was confirmed that the adhesion was good.

In addition, emission analysis confirmed that the elution of Ca and Fe was reduced.

Determination of eluted Na Main treatment 0.010 ppm Untreated 0.770 ppm (Comparative Example) In the examples, the treatment without using the heating method of the heating portion caused a faint haze in appearance, and the effect of preventing alkali elution was poor. The elution amount was 0.03 to 0.2 ppm.

〔The invention's effect〕

According to the improved CVD method of the present invention, the silyltetraisocyanate used in the treatment is exposed to the high temperature required to obtain its vapor pressure continuously during preparation and operation as in the conventional method. Absent. The compound dispersed in the carrier gas atomized by the ultrasonic method at the room temperature or in the vicinity thereof is transferred, and in the second step, the dispersion is heated and gasified, and the mixed gas of the compound gas and the carrier gas is mixed. Become. This mixed gas is brought into contact with the surface of a medical glass product to form a silica film to prevent elution of alkali and the like.

[Brief description of the drawings]

The figure is an explanatory view showing an example of an apparatus suitable for carrying out the method of the present invention. A: generated part, B: heated part, C: processed part, 1
... liquid tank, 2 ... ultrasonic oscillator, 3 ... gas inlet, 5 ... opening, 10 ... heater, 11 ... heat insulating material, 15 ...
… Process transfer tube, 17… Air cylinder, 20… Ampule, 21… Discharge needle.

Continuation of the front page (56) References JP-A-2-22106 (JP, A) JP-A-62-207870 (JP, A) JP-A-63-261700 (JP, A) (58) Fields investigated (Int .Cl. ⁶ , DB name) C03C 17/00-17/44 C23C 16/00-16/56

Claims (1)

(57) [Claims] 1. Silicate tetraisocyanate is atomized by an ultrasonic method and dispersed in a carrier gas, and the dispersion is heated to be gasified and brought into contact with the inner surface of a medical glass product to heat and form a silica film to form a silica product. Method to prevent elution of alkali etc. from dough.